Fire-extinguisher



Dec. 31, 1957 w. CLIFF-0RD ETA],- 2,818,121

FIRE-EXTINGUISHER Filed Feb. .6, 1956 5 Sheets-Shed 1 Dec. 31, 1957 w. J. CLIFFORD El'AL 2,818,121

FIRE-EXTINGUISHER 5 Sheets-Sheet 2 Filed Feb. 6, 1956 Dec. 31, 1957 w. J. CLIFFORD ETAL FIRE-EXTINGUISHER 5 Sheets-Sheet 5 Filed Feb. 6, 1956 V. ,1. n l I II I: rllll/ i I11 I lllllm t a Dec. 31, 1957 w. J. CLIFFORD ET AL 2,818,121

FIRE-EXTINGUISHER Filed Feb. 6, 1956 5 Sheets-Sheet 4 Dec. 31, 1957 w. J; CLIFFORD ETAL 2,818,121

FIRE-EXTINGUISHER Filed Feb. 6, 1956 5 Sheets-Sheet 5 nit FlRE-EXTINGUISHER Application February 6, 1956, Serial No. 563,776

Claims priority, application Great Britain February 10, 1955 8 Claims. c1. 169--9) This invention relates to fire-extinguishing apparatus of the kind in which a fire-extinguishing powder is expelled from a closed container through a discharge tube by introducing'a gas under pressure from a cylinder or the like, which may be separate from, within or mounted on the container. The gas under pressure is usually carbon dioxide, and the discharge tube is usually a hose.

It is important to ensure that the particles of powder are loosened and disturbed before any of the powder is driven out of the container, since otherwise compacted lumpsof powder may clog the discharge tube or any passages leading to it. It is convenient to disturb the powder by introducing at least some of the gas below the normal powder level while maintaining the container closed, and subsequently allowing the gas to expel the powder.

The principal object of this invention is to enable the necessary sequence of steps to take place automatically once the gas has been released from its cylinder.

Another object of this invention is to provide a fireextinguishing apparatus containing a dry extinguishing powder in which means are provided for initially disturbing the powder and thereafter for discharging the powder under continuously decreasing pressure.

A further object of the invention is to provide a novel set of interrelated valves for controlling the operation of a dry powder fire extinguisher.

In our invention a pressure-operated diverting valve set to deliver the gas into the space in the container in which the powder lies to disturb the powder is exposed to the pressure in the container to be actuated upon a predetermined rise in pressure in the container to divert the gas to two difierent points, namely a flow-controlling device through which the gas thereafter flows to the container and an isolating valve which is set to isolate the discharge tube from the interior of the container and which is actuated by the diverted gas to allow the powder to be driven out of the container to the discharge tube.

The flow-controlling device may serve to restrict the rate of flow into the container during the discharge of the powder to a value such that the pressure in the container falls continuously; or it may stop the flow completely on the pressure in the container reaching a predetermined value. Preferably it performs both these functions.

The reason why the flow-controlling device should ensure that the pressure in the container falls continuously is that if the pressure falls minute pockets of gas expand and break up any powder compacts, whereas if the pressure rises any such compacts are not broken up and cause the flow of powder to be uneven. Therefore the preferred device includes an orifice of a size so correlated with that of the discharge tube and any other passages through which the gas flows that the desired result is obtained.

The reason why the flow-controlling device should stop the flow completely on the pressure in the container reaching a predetermined value is that the pressure in the cylinder or the like is commonly so high, e. g. 800 lbs. per square inch, that it is undesirable to allow all the. gas to atent "ice enter the container at once, since the pressure init: would be initially too high for conveniently, discharging the powder at astable. rate. Now the actual discharge; of powder is usually controlled-by a. manual valve onthe discharge hose or other'discharge tube. If it is-nohopened immediately the diverting valve moves, or isclosedfor any length of time after once being opened, the pressure in. the container will build up. Thereforethe preferred flow-controlling device also includes a valvev actuated by a pressure-responsive deviceexposed to the pressure-i11- side the container and operative to stop the entry;of;gas into the container if a' predeterminedfpressureisreached in the container during operation.

In apparatus of the kind inquestion the. powder; is driven to the dischargetube'through an outlet tubeconnected to the interior of the container. Thistube, which is often a dip tube extending downwards from the top of the container, but may be a'tube leading from the bottom of the container, is liable to be clogged. Therefore we prefer to introduce the gas initially through the outlet tube to clear it. For this purposewe connect the cylinder or the like to a chamber in the isolating valvewhiclr is also connectedto the outlet tube.-

The preferred apparatus will now be describedin detail with reference tothe accompanying drawings, in which:

Figure 1 is a diagram showing the apparatus in outline and indicates the gas'flows duringthe disturbanceof the powder;

Figure 2 is a diagram similar to l-Figure 1 and indicates the gas flows duringdischarge;

Figure 3 is a diagrammatic showing: of the various valves in more detail and corresponds to Figure 1;

Figure 4 is similar to Figure 3 but corresponds to'Fig ure 2;

Figure 5 is a side elevation of the preferred embodiment of the invention;

Figure 6 is a planet this embodiment;

Figure 7 is an enlarged plan view of a valve-assembly in the preferrediembodiment;

Figure 8 is a section on the line V1IIVIII in Fig: ure7;

Figure 9 is a. section on the line IX-IX'in Figurefl; and

Figure 10 is a section. on the line XX in Figure 7;

The apparatus shown in Figures- 1 and 2 comprises a container 1 for dry fire-extinguishing powder which is tobe expelled through a dip tube 3 to a discharge hose 4 by carbon dioxide released from a cylinder 5 in which it is stored under high pressure. Three valves are mounted on the top of the container, namely a divert-ing valve 6-, an isolating valve. 7: and a flow-controlling device 8.

The cylinder 5 is connected by a pipe 9' to the diverting valve 6 and at the start of the operation flows through this valve to a pipe 10 leading to a chamber 11 in the isolating valve 7; The top of the dip tube 3 opens into this chamber, which is separated from another chamber 12 by a wall 13; through which apiston rod 14 passes. On one side of the wall 13 the rod 14- carries a valve member 15 and on the other side it' carries a piston 16 subjected to the action of a compression spring 17. A discharge port 18 leading to a connection 19' for the hose 4 is controlled by the valve member 15, being closed unless the piston is moved to the left as seen in the drawings against the spring 17. Thus: the gas entering the chamber 11 cannot pass tothe-hose 4', but is all delivered down the dip tube 3" to disturb the powder.

The pressure in the container 1 builds up rapidly and on reaching: a predetermined value operates the diverting valve 6. This valve includes a valve member which serves to connect the pipe 9 to the pipe 10 when in the position shown in Figure 1 but to shut off the pipe 10 when in the position shown in Figure 2 and instead to connect the pipe 9 to two further pipes 21 and 22. The pipe 21 leads to the chamber 12, and the gas entering this chamber forces the piston 16 to the left and so opens the port 18, with the result that discharge of powder begins. The pipe 22 leads to the flowcontrolling device 8, so that the gas now enters the container 1 at a lower rate.

It will be seen that the isolating valve 7 ensures that there is no loss of pressure by flow through the discharge outlet until the diverting valve is actuated to let gas flow through the pipe 21. The discharge of powder onto a fire is controlled by a manually-operated valve (not shown) close to a discharge nozzle on the hose 4, but this valve may be opened prematurely, whereas the isolating valve 7 will remain closed and prevent discharge until the diverting valve 6 has been actuated. i The flow-controlling device 8 ensures that when the desired pressure has been built up in the container 1 during the step of disturbing the powder, the gas entering to expel the powder through the opened isolating valve 7 flows at a rate such that the pressure in the container falls so long as the powder discharge proceeds normally. The device 8 is a valve, made as described in our application Serial No. 563,789, filed February 6, 1956, so that it will close automatically if the pressure rises during discharge as a result of closure of a manually operated valve at the end of the hose 4 or of blockage of any of the parts through which the powder flows.

As shown in Figures 3 and 4 the flow-controlling device 8 comprises a casing 23 in which a chamber 24 is formed, the pipe 22 leading into this chamber. The bottom of the chamber 24 is formed by a wall 25 in which there is an orifice 26 leading to a flaring passage 27. The chamber is also bounded by a wall 28 through which a valve stem 29 passes, this stern carrying a valve member 30 and having a head 31. A spring 32 surrounds the stem to urge the head upwards and therefore to maintain the orifice 26 open. A hood 33 around part of the casing 23 bounds a passage 34 leading from the interior of the container 1 to a bellows 35, the lower end of which is rigid with the head 31. Thus, on the pressure in the container 1 reaching a predetermined value, the bellows expands so much as to cause the valve member 30 to close the orifice 26.

In designing the extinguisher, the time required for complete discharge of the contents and the pressure range in the container during discharge, say initially 150 lbs. per square inch falling to 80 lbs. per square inch, are first decided. The diameter of the outlet tube 19 and discharge hose 4- are chosen to allow this rate of discharge to be obtained, and then the size of the orifice 26 is calculated to ensure that the gas will enter through it at a rate which makes the pressure in the container fall continuously.

The construction of the diverting valve 6 is also shown in Figures 3 and 4. The valve member 20 has a stem 36 which lies in a cylindrical passage 37 in a wall 38 and which carries two valve discs 39 and 40. These serve to close the opposite ends of the passage 37 and so direct the flow of gas to a chamber 41 in Figure 3 and thence to the pipe 10 or to a chamber 42 in Figure 4 and thence to the pipes 21 and 22. The stem 36 passes downwards through a gland 43 into a bellows 44 which lies inside the container 1. A spring 45 around the stem expands the bellows so the normal position of the valve member 20 is that shown in Figure 1. When the pressure in the container 1 has risen to the predetermined value, it overcomes the spring 45, with the result that the stem 36 moves, carrying the valve disc 39 0E its seat and the valve disc 40 onto its seat,

4 and thus diverting the gas to the isolating valve 7. The two valve discs are preferably of equal effective areas.

To enable the hose 4 to be cleared it the fire is extinguished before the container has been completely discharged, a by-pass connection is provided between the container 1 and the connecting piece 19 as shown in Figures 1 and 2 and is controlled by a manually operated valve comprising a valve member 47 lying inside the con= tainer, a stem 48 passing through the connecting piece 19, a head 49 and a spring 50 surrounding the stem beneath the head to maintain the valve closed. This valve can be opened also if the pressure in the container must be released at any time without expelling powder.

As one of various modifications which may be made, the gas for disturbing the powder in the container may be introduced through a tube terminating in the middle of the container, and then this gas need not pass through the isolating valve. Moreover in such a case the tube may be used as the means through which the gas is subsequently introduced into the container under the reduced pressure, a connection being provided between it and the outlet side of the reducing valve.

The apparatus shown in Figures 5 to 10 works on the principle illustrated by Figures 1 to 4, and the same reference numerals are used to identify the corresponding parts.

In this apparatus the container 1 and carbon dioxide cylinder 5 are mounted on a trolley with Wheels 51 and a handle 52. The container is charged with powder through an opening closed by a cap 53. The cylinder 5 has a squeeze-grip valve 54- by which the release of the gas into the pipe 9 is controlled. The hose 4, which may be stored as a coil around the container 1 as shown in Figures 5 and 6, terminates in a discharge nozzle 55 controlled by a valve.

The isolating valve 7 is best shown in Figure 8. The wall 13 is made in one piece with a casing 56 housing the spring 17 and closed by an end cap 5'7 having an opening 58 to relieve the internal pressure. The casing 57 is screwed into a block 59 which also forms the connecting piece 19 and bounds the chamber 11.

The diverting valve 6 is housed in the same block 59.

We claim:

1. A fire-extinguishing apparatus comprising a container adapted to hold a fire-extinguishing powder and to permit the discharge of the powder by gas under pressure, said container comprising first and second gas inlets, said first inlet being located in the powder containing space in said container, valve means in said discharge tube, pressure-responsive means for actuating said valve to the open position, a source of gas under pressure, means including a pressure-operated diverting valve normally connecting said source to the first of said inlets, said diverting valve being responsive to the pressure in said container and operative upon a predetermined pressure being attained therein to divert the gas from said first inlet to both said second inlet and to the actuating means for said discharge valve means.

2. A fire-extinguishing apparatus according to claim 1 and further comprising means including an orifice in the second inlet valve to continuously decrease the pressure in the container during discharge of the powder.

3. A fire-extinguishing apparatus according to claim 2 and further comprising valve means in said second inlet, and means responsive to the internal pressure in the cylinder to actuate said valve means, said actuating means closing said valve means when the pressure in the container reaches a predetermined amount.

4. A fire-extinguishing apparatus according to claim 3, wherein said valve means included a lift member directly closing the orifice.

5. A fire-extinguishing apparatus comprising a container adapted to hold a fire-extinguishing powder and to permit the discharge of the powder by gas under pressure, said container comprising first and second gas inlets,

said first inlet comprising a chamber into which gas is fed, and a tube leading from said chamber and extending into the powder containing space in said container, said tube further serving as the discharge tube, a discharge outlet leading from said chamber valve means in said discharge outlet, and pressure-responsive means for actuating said valve means to the open position, a source of gas under pressure, means including a pressure-operated diverting valve normally connecting said source to said chamber, said diverting valve being responsive to the pressure in said container and operative upon a predetermined pressure being attained therein to divert the gas from said first inlet to both said second inlet and to the actuating means for said discharge valve means.

6. Apparatus according to claim 5 wherein said first in let comprises a first chamber into which gas is fed, a tube leading from said chamber and extending into the powder containing space in said container, said tube further serving to discharge the powder from said container, at discharge outlet leading from said chamber, valve means in said discharge outlet, a second chamber adjoining said first chamber, piston means in said second chamber, shaft means connecting said piston and valve means, and spring means tending to hold said valve means closed against the action of gas pressure on said piston.

7. An apparatus according to claim 5 in which the diverting valve comprises a valve member carried by a stem which is moved against spring action by the pressureresponsive device that actuates the discharge valve.

8. An apparatus according to claim 5 in which a bypass connection is provided between the container and the downstream side of the discharge valve and is controlled by a manually operated valve.

References Cited in the file of this patent UNITED STATES PATENTS 1,347,358 Adams July 20, 1920 1,889,163 VogelJorgcnsen Nov. 29, 1932 2,681,115 Guise June 15, 1954 

